oom-kill: fix NUMA constraint check with nodemask

Fix node-oriented allocation handling in oom-kill.c I myself think of this
as a bugfix not as an ehnancement.

In these days, things are changed as
  - alloc_pages() eats nodemask as its arguments, __alloc_pages_nodemask().
  - mempolicy don't maintain its own private zonelists.
  (And cpuset doesn't use nodemask for __alloc_pages_nodemask())

So, current oom-killer's check function is wrong.

This patch does
  - check nodemask, if nodemask && nodemask doesn't cover all
    node_states[N_HIGH_MEMORY], this is CONSTRAINT_MEMORY_POLICY.
  - Scan all zonelist under nodemask, if it hits cpuset's wall
    this faiulre is from cpuset.
And
  - modifies the caller of out_of_memory not to call oom if __GFP_THISNODE.
    This doesn't change "current" behavior. If callers use __GFP_THISNODE
    it should handle "page allocation failure" by itself.

  - handle __GFP_NOFAIL+__GFP_THISNODE path.
    This is something like a FIXME but this gfpmask is not used now.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hioryu@jp.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c
index 44203ff..1ae2de7 100644 (file)
--- a/drivers/char/sysrq.c
+++ b/drivers/char/sysrq.c
@@ -339,7 +339,7 @@ static struct sysrq_key_op sysrq_term_op = {
 
 static void moom_callback(struct work_struct *ignored)
 {
-       out_of_memory(node_zonelist(0, GFP_KERNEL), GFP_KERNEL, 0);
+       out_of_memory(node_zonelist(0, GFP_KERNEL), GFP_KERNEL, 0, NULL);
 }
 
 static DECLARE_WORK(moom_work, moom_callback);

diff --git a/include/linux/oom.h b/include/linux/oom.h
index 6aac5fe..5376623 100644 (file)
--- a/include/linux/oom.h
+++ b/include/linux/oom.h
@@ -10,6 +10,7 @@
 #ifdef __KERNEL__
 
 #include <linux/types.h>
+#include <linux/nodemask.h>
 
 struct zonelist;
 struct notifier_block;
@@ -26,7 +27,8 @@ enum oom_constraint {
 extern int try_set_zone_oom(struct zonelist *zonelist, gfp_t gfp_flags);
 extern void clear_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_flags);
 
-extern void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order);
+extern void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
+               int order, nodemask_t *mask);
 extern int register_oom_notifier(struct notifier_block *nb);
 extern int unregister_oom_notifier(struct notifier_block *nb);
 

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 6bb8a7a..25c679e 100644 (file)
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -196,27 +196,46 @@ unsigned long badness(struct task_struct *p, unsigned long uptime)
 /*
  * Determine the type of allocation constraint.
  */
-static inline enum oom_constraint constrained_alloc(struct zonelist *zonelist,
-                                                   gfp_t gfp_mask)
-{
 #ifdef CONFIG_NUMA
+static enum oom_constraint constrained_alloc(struct zonelist *zonelist,
+                                   gfp_t gfp_mask, nodemask_t *nodemask)
+{
        struct zone *zone;
        struct zoneref *z;
        enum zone_type high_zoneidx = gfp_zone(gfp_mask);
-       nodemask_t nodes = node_states[N_HIGH_MEMORY];
 
-       for_each_zone_zonelist(zone, z, zonelist, high_zoneidx)
-               if (cpuset_zone_allowed_softwall(zone, gfp_mask))
-                       node_clear(zone_to_nid(zone), nodes);
-               else
-                       return CONSTRAINT_CPUSET;
+       /*
+        * Reach here only when __GFP_NOFAIL is used. So, we should avoid
+        * to kill current.We have to random task kill in this case.
+        * Hopefully, CONSTRAINT_THISNODE...but no way to handle it, now.
+        */
+       if (gfp_mask & __GFP_THISNODE)
+               return CONSTRAINT_NONE;
 
-       if (!nodes_empty(nodes))
+       /*
+        * The nodemask here is a nodemask passed to alloc_pages(). Now,
+        * cpuset doesn't use this nodemask for its hardwall/softwall/hierarchy
+        * feature. mempolicy is an only user of nodemask here.
+        * check mempolicy's nodemask contains all N_HIGH_MEMORY
+        */
+       if (nodemask && !nodes_subset(node_states[N_HIGH_MEMORY], *nodemask))
                return CONSTRAINT_MEMORY_POLICY;
-#endif
+
+       /* Check this allocation failure is caused by cpuset's wall function */
+       for_each_zone_zonelist_nodemask(zone, z, zonelist,
+                       high_zoneidx, nodemask)
+               if (!cpuset_zone_allowed_softwall(zone, gfp_mask))
+                       return CONSTRAINT_CPUSET;
 
        return CONSTRAINT_NONE;
 }
+#else
+static enum oom_constraint constrained_alloc(struct zonelist *zonelist,
+                               gfp_t gfp_mask, nodemask_t *nodemask)
+{
+       return CONSTRAINT_NONE;
+}
+#endif
 
 /*
  * Simple selection loop. We chose the process with the highest
@@ -613,7 +632,8 @@ rest_and_return:
  * OR try to be smart about which process to kill. Note that we
  * don't have to be perfect here, we just have to be good.
  */
-void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order)
+void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
+               int order, nodemask_t *nodemask)
 {
        unsigned long freed = 0;
        enum oom_constraint constraint;
@@ -632,7 +652,7 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order)
         * Check if there were limitations on the allocation (only relevant for
         * NUMA) that may require different handling.
         */
-       constraint = constrained_alloc(zonelist, gfp_mask);
+       constraint = constrained_alloc(zonelist, gfp_mask, nodemask);
        read_lock(&tasklist_lock);
 
        switch (constraint) {

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 59d2e88..850c4a7 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1654,12 +1654,22 @@ __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
        if (page)
                goto out;
 
-       /* The OOM killer will not help higher order allocs */
-       if (order > PAGE_ALLOC_COSTLY_ORDER && !(gfp_mask & __GFP_NOFAIL))
-               goto out;
-
+       if (!(gfp_mask & __GFP_NOFAIL)) {
+               /* The OOM killer will not help higher order allocs */
+               if (order > PAGE_ALLOC_COSTLY_ORDER)
+                       goto out;
+               /*
+                * GFP_THISNODE contains __GFP_NORETRY and we never hit this.
+                * Sanity check for bare calls of __GFP_THISNODE, not real OOM.
+                * The caller should handle page allocation failure by itself if
+                * it specifies __GFP_THISNODE.
+                * Note: Hugepage uses it but will hit PAGE_ALLOC_COSTLY_ORDER.
+                */
+               if (gfp_mask & __GFP_THISNODE)
+                       goto out;
+       }
        /* Exhausted what can be done so it's blamo time */
-       out_of_memory(zonelist, gfp_mask, order);
+       out_of_memory(zonelist, gfp_mask, order, nodemask);
 
 out:
        clear_zonelist_oom(zonelist, gfp_mask);
@@ -3123,7 +3133,7 @@ static int __cpuinit process_zones(int cpu)
 
                if (percpu_pagelist_fraction)
                        setup_pagelist_highmark(zone_pcp(zone, cpu),
-                               (zone->present_pages / percpu_pagelist_fraction));
+                           (zone->present_pages / percpu_pagelist_fraction));
        }
 
        return 0;